Monday, November 24, 2014

Where is the Thanksgiving Day storm?

For about 3 weeks (look back in the past three posts) I had discussed a possible storm around (several days before to after) Thanksgiving.  In the blog I did last Friday (click here) I talked about the anomalously strong jet stream extended across the Pacific and how it would likely amplify (buckle). That process is starting to happen as of late Sunday night.

I had a feeling that with this buckling that there would be major cyclogenesis (deep low developing) somewhere from the central part of the country to the east coast.  It often is impossible to predict this location much in advance, until a pattern is established and starts to cycle.

On the following satellite image, you can't see the storm that brought rain and much warmer air to the snow battered Buffalo, NY area.  Another weaker small storm (denoted by the L) was moving through Illinois and will bring additional precipitation to western New York.  The two lines with arrows indicates the positioning of two branches of the westerlies (jet stream).  The one in red is the result of the buckling of the extended jet stream noted above.  The second blue one is the polar extension of the jet stream.  The two X's represent energy in the flow that will become the first of two storms.

It now appears that this buckling will result in several storms instead of just one major one.  The first will bring heavy snow and wind to the western Great Lakes late today and tonight (24th).  The second will amplify into the Mississippi Valley and eventually deepen and move up the east coast.  If you look at the Weather Prediction Center's precipitation forecast of precipitation for the next 7 days there is a swath of heavy precipitation on the east coast.  That leaves the High Plains region without much of anything!

WPC precipitation forecast

Early on it appeared pretty likely that Arctic air would make a return visit late this month behind these potential systems.  The cold air is in place behind a strong cold front, but it now appears that much of this cold air will move southeast instead of south.

Map of the current location of the Arctic air and fronts.

It is amazing that the various numerical weather prediction computer models have been all over the place regarding impacts from the evolution of this pattern.  One in particular from the European weather center (ECMWF - it's generally the most accurate) had been indicating possible snow across the central plains for Thanksgiving.  Now it is indicating very mild conditions for Thursday and Friday.  Another model that goes 6 to 8 weeks into the future was indicating a very cold stretch of 7-9 days, starting Thursday.  But it too has backed off considerably.

Another long range computer model's output showing the cold for Dodge City....

Thankfully the above forecast output is not likely to verify - at least this time.

I think the story line is that until the pattern starts to repeat and cycle, it will be tough to have much lead time on any systems.

More later...

Friday, November 21, 2014

Update - November 21, 2014

Finally the Arctic November chill has moved out of the high plains, although with low clouds and fog it was still rather chilly across the eastern high plains Friday afternoon.  The Arctic cold that we endured was one of the top 3 coldest periods for November.   The average temperature at Dodge City from November 11-17 was only 21.3 degrees, or about 23 degrees below normal!  This is the 3rd coldest 7 day stretch in November for Dodge City, since records began in 1875.  The 2nd coldest 7 day stretch was in 1952 when the average temperature was 19.8 degrees.  The coldest was way back in 1880 when the average was as astonishing 11.4 degrees (November 16-22)!  Compare that to normal which is 44 degrees!

Snowfall across the plains last weekend from 2 separate systems ranged from  less than one inch to 4 1/2 inches, depending on your location. 

From the post I did on the 7th of November and the one I did on the 19th, I discussed a potential major storm around Thanksgiving.  Any thoughts of WHERE this might occur was up in the air as the system was not showing up on any numerical weather guidance and really not showing up on analysis products.  As of Friday (this writing), I still don't have a real good feel for the development or placement.  For a few days the European forecast model (ECMWF) did have a system for next week - and it's usually the most accurate that is available to view.  However, during the past few iterations it didn't have anything.

On the map below the most notable feature is the very strong and anomalously strong jet stream across the Pacific ocean basin.  This configuration and magnitude is very unstable.  In most cases as this unstable and energetic jet breaks down, chaos ensues in the form of rapid intensification and downstream amplification of the upper level winds.  During the cold months this usually means a significant storm.  But the $10 million dollar question is exactly when and where!  Numerical weather prediction models are all over the place and therefore are of no help.

Satellite image showing the strong jet (red arrows)

Friday afternoon there was a rather significant storm over Arizona which will bring widespread rain to central/east Texas and eastern Oklahoma and into the Mississippi Valley.  Then eventually heavy rains on the east coast.

The Weather Prediction Center of the NWS offers this solution over the next 7 days....
As far as the Thanksgiving storm...I just don't know yet.  If it is going to show up as an organizing storm, it might not be until Monday or Tuesday.  But when it does start developing it might do so very rapidly.  Right now my gut feeling is that it will affect areas from Chicago to the northeast or New England areas.  If you will be flying then you should probably expect delays.

I'll try and follow up on Monday and see what is showing up.  Earlier this fall I talked about repeatable weather systems, once they establish themselves in the Fall.  I'm not finding that repeating system, yet.

Enjoy the first half of the weekend.  Colder (though not Arctic cold) temperatures are in store for Sunday/Monday.

Wednesday, November 19, 2014

Update - November 19, 2014

Probably the biggest news during the last few days is the absurd amount of lake effect snow that the eastern Great Lakes has received and will continue to receive.  Google "lake effect snow 2014" and look at some of the crazy photos and video!  As of this afternoon there were observers that had already picked up 6 feet of snow and more was on the way.  The most awesome time lapse I've witnessed can be found here.

Back to high plains weather....

The temperature at the Dodge City airport on the 10th of November rose to 80 degrees at 1245 PM but had fallen to 22 by midnight, and 16 by Tuesday morning.  That's ridiculous! The brutal change from a relatively mild Fall to Winter that was ushered in on the heels of the November cold is letting up a bit.   A few more brief surges of colder air can be expected during the next 5 days (intermixed with mild temperatures).  At least there has been a warmup.  However, the warmup has been and will be tempered by snow cover.  The map below shows what the snow cover that was observed on the 18th.

If you read back on the past few posts, I discussed the pattern shift that caused this outbreak of cold.  Basically the change that took place has locked into place. This bothers me a little bit.  I was expecting this shift to occur.  But, I did not expect that particular pattern to persist this long (at least for now) and the longer it does persist the more likely that it will repeat often into the deep of winter.  The upshot of that scenario is a tendency for a cold and dry winter (below normal temps, below normal precip).

On the satellite image above, the blue line with arrows denotes the polar jet stream, capable of bringing Arctic air into the U.S., which has been ongoing since the 10th.  If that persists, then there will be periodic Arctic fronts sweeping across the country (and High Plains).   The issue for now is the blocking that is anchored over western Canada.  First, it is preventing the moist Pacific jet stream from entering into the country from the west.  Second, it is allowing the persistence of the polar jet to be in the same configuration.  That blocking should break down soon.  However, as it does break down the jet stream may reconfigure in such as fashion as to bring additional cold to the U.S., with a threat of precipitation, especially if it shifts westward.

In the blog I did on November 7th (click here for that discussion) I stated "the atmosphere should reorganize and re-energize and then could unleash some nastiness around Thanksgiving.  There is a small signal of a high impact weather event  during the last 5 days of the month.  The only problem, I don't know if it'll be in the central plains, midwest, or north.  I'd bet though that there will be travel issues across the country about then."  That is still a very real possibility, even though the long range computer forecast models from the U.S. shows NOTHING!  Even if the high plains misses out on a potential storm, there will likely be another outbreak of Arctic air.  I'll update Friday or next Monday.

Beyond next week there are signals to high impact events the first 10 days of December, especially for additional cold.

Wednesday, November 12, 2014

Quick Update - November 12, 2014

Go to the previous link here where I discussed this brutal cold we're experiencing for November.

The high temperatures today (Wednesday the 12th) where record setting at many sites.

Plus, the mercury may not rise much above freezing right on through the remainder of the week.

There is still a lot of uncertainty about the weekend weather.  I, unfortunately, have other obligations and cannot update much more at this time.

Friday, November 7, 2014

Update - November 7, 2014

I hope everyone is ready for the cold!  In the previous post (click here) I mentioned the cold coming up for this next week "By the middle part of next week high temperatures may be in the 20s/30s and lows in the single digits to teens".  This post I'm writing today is an update to those thoughts.

As expected, the remnants of what was once Typhoon Nuri is transitioning into a super deep and extremely strong ex-tropical low across the Bering See/Aleutian islands.  The video below shows the wind pattern with that system and with other weather systems.  Click on the video to play.


There have been forecasts of winds to be up to 100 MPH and wave heights well in excess of 50 feet (some estimates near 100 feet if that can be believed)!  This intense storm up there will force warm air north into the Arctic.  The frigid air up in the Arctic as of today (Friday) will therefore be forced south, right towards the U.S..  Additional downstream propagating energy will also produce other mechanisms to displace the cold.  So, the result for us across the high plains will be an end to the relatively mild Fall and the start to winter conditions.  Most of the impacts this time will be from the cold and not snow or ice.  Yes, there could very well be a little snow during the stretch of the cold but amounts, if any, should be minimal.

At 9 AM this Friday morning the cold air was already headed south but at a slow and steady pace.  Temperatures across northern Canada were around 15 below zero (that is not wind chill).  The front that was the leading edge to the winter cold will arrive across Kansas sometime Monday.

The following video is output from one of the global forecasting computer models that generates a simulated forecast.  This one shows the invading cold, but don't get caught up in the numbers.  It is actually too warm! 


Temperatures by mid-week (~12th) may struggle to get out of the upper teens and 20s for highs! Lows will dip well into the teens and single digits at some locations.   Although there may be a brief warmup (warmup may be misleading) Friday or Saturday, a second and perhaps even colder airmass could invade the area Sunday and Monday (16th-17th).  One of the long range global models has temperatures down to 5 to 15 below zero as far south as southwest Kansas!

Beyond this next 7 to 10 day period the atmosphere should reorganize and re-energize and then could unleash some nastiness around Thanksgiving.  There is a small signal of a high impact weather event  during the last 5 days of the month.  The only problem, I don't know if it'll be in the central plains, midwest, or north.  I'd bet though that there will be travel issues across the country about then.  I'll update that  possibility at a later time.

Tuesday, November 4, 2014

Update - November 4, 2014

I've been a professional Meteorologist since 1983.  The first six years were in the private sector where I was manager of forecasting operations and the remainder working for the National Weather Service (in Des Moines, IA and in Dodge City) where I've been both a Lead Forecaster and a Warning Coordination Meteorologist.  In those years I've gained a lot of experience.  One of my life's experiences is that once I make a forecast and it's my gut feeling, I stick with it!  Don't change that initial forecast!   Well, I'm breaking that wisdom.  If you go to the outlook that I issued on October 23 (click here for that discussion), you can see my outlook at the bottom of that post.  I've already made a tweak to the temperature forecast for the winter months of December, January, and February.  I'm already seeing some signs that the cold may dominate early on (not sure about late winter yet) so the average for the 3 months may be colder than originally thought.

Updated forecast made on November 4, 2014
The initial temperature outlook can be viewed by clicking here.

I've left the precipitation forecast as is.   BTW, at our office we have a "guess how much snow will fall" and I guessed 29.8" of snow at the Dodge City airport from November through May.   Totals will be highly variable across the plains though.

One of the reasons I'm leaning more towards the cold side is that vast amount of snow cover that is already across Eurasia and Siberia.  It is reportedly the most seen since the mid 1970s!  Usually this does not bode for a mild/warm winter across the U.S., and since I was already expecting  a pattern conducive to cold, I just had to make the adjustment.  The following map shows the snow and ice cover across the northern hemisphere as of November 3...

You might notice the lack of snow cover across North America.  Despite the record setting snows across the eastern part of the country late this past weekend, the overall snow cover across the U.S. is actually a little less than normal.  Also, there really hasn't been extremely cold weather yet (except for the far east and southeast part of the U.S.) and in fact much of the western half of Kansas has not had a "killing" freeze!  But, that is about to change and change big!

If you follow the weather at all you may have heard about the super typhoon across the western Pacific south of Japan.  Nuri is it's name and it is quite powerful for so late in the season.  As Nuri heads north it will interact with a anonymously strong jet stream and will become an extremely deep and strong ex-tropical cyclone as it heads towards the Bering Sea.  In fact there are predictions of wave heights of 50 feet possible in the Bering Sea.  WOW!  This powerful storm and the track will help force a shot of very cold air to head south into the U.S. in 7 to 10 days (probably closer to 7).  This cold air will likely spread  deep into the plains and midwest.  By the middle part of next week high temperatures may be in the 20s/30s and lows in the single digits to teens, at least that seems a distinct possibility.   The way the NWS operates this may not show up in the forecast until a few days out - it will likely just be a gradual trend towards colder.   There does not appear to be much chance in the way of precipitation though.

The following satellite image shows the feature I'm talking about...

A look at recent precipitation and the drought

Late Sunday night and early Monday there was a bit of precipitation that moved out of Colorado and New Mexico and into Kansas.  The amounts were generally very light except down in New Mexico.

For October the rains were a little more generous for many folks, but lacked significantly for others.  By far the greatest amounts were across eastern Kansas, Oklahoma and into the Mississippi valley.  Click for a larger version.

At Dodge City the total was above average.  The following map for October precipitation has a different color curve than the one above but it shows the high plains a little closer.  Click for a larger version.

The drought continues across much of the western part of the country and also across parts of the plains.  The winter months are not a good time to improve on the drought since it's the driest part of the year, historically.

One final thought....Thanksgiving.  I've got little hunch that there will be a very high impact weather event around that time, somewhere across the central plains into the midwest.  Obviously this is quite a ways out but it is something I will be watching carefully.  Historically the highest threat for a blizzard across western Kansas is during three periods:  1) November 20-30, 2) January 1-5, 3) March 18-22.  This is only based on climatology.

I'll try for another update next Wednesday.